绝对值不大于3的所有整数的积等于______.
绝对值不大于3的所有整数有:0,±1,±2,±3,
∴它们的积为0.
故答案为0.
-----Who helped ________with the job ?
-----Nobody , They did it by______.
A.them, them
B.them, themselves
C.themselves, them
D.themselves, themselves
引起传染病的细菌、病毒和寄生虫等生物,称为 。